Known inboard boat drives comprise a steering and propulsion unit arranged underwater, which can be pivoted about a vertical axis. Propulsion is produced by one or two propellers whose rotational axis can be pivoted by the steering unit. Thanks to the ability of the propulsion vector to be pivoted, a steering action for the boat is achieved. The propulsion and steering unit comprises a vertically arranged column which accommodates the driveshaft for the propeller and which passes through a bottom plate set into the boat's hull, this also being known as the connecting piece. In known boat drives the pivotable steering and propulsion unit is supported and sealed relative to the hull opening by elastic rings, i.e. at the same time reaction forces resulting from the propeller thrust are transmitted directly into the hull. A disadvantage of the known sealing arrangement is that the elastic rings are subjected to relatively large forces and must therefore have relatively high elasticity, which is less advantageous for a good sealing action. However, such a seal is prone to increased wear due to relative movements between the seal and the component to be sealed.
From WO 2005/005249 A1 a similarly pivotable boat drive with a traction double propeller is known.